This invention relates generally to non-clogging vertical turbine pumps and more particularly to flushable bearing housings which are removable from the suction end of the pump without disassembly of the attached column pipe.
The lower bowl bearing in a vertical turbine pump used for pumping liquids which contain entrained solids is the one most subject to wear and most often in need of replacement. This is because of exposure of the bearing to the abrasive and corrosive effects of the solids-containing pumped fluid which leaks between the pump shaft and the bowl adjacent to the impeller hub and infiltrates between the bearing and the rotating shaft. In some such pumps, a wear ring is pressed into the lower end of the bowl and provides a close clearance around the hub of the impeller to limit the size of particles entering the bearing from the contaminated pumped fluid. It also reduces the total amount of infiltrating fluid. This wear ring also must be replaced when it deteriorates, thereby necessitating extracting the worn ring from the bowl using a special puller and pressing a replacement ring into the bowl.
Commonly, in such pumps, flushing with clean fluid is provided to remove wear particles and abrasive and corrosive material which infiltrates the lower bowl bearing from the pumped fluid. In most cases of bearing failure, only the lower bowl bearing requires replacement. This is attributable to the fact that the lower bearing is closest to the pumped fluid and is exposed to the abrasive and corrosive effects of any infiltration of the pumped fluid into the flushing tube. The bearing serves to further block pumped fluid infiltration up the flushing tube and thereby protects the upper bearings.
Since vertical turbine pumps are commonly assembled from the bottom up, the bearings are pressed into the bowl, the shaft is inserted through the bearings, the impeller is fastened to the shaft, and the suction head is attached to the bowl. The discharge conduit is attached above the bowl, and the motor, electrical, water, and piping connections are made.
To replace the bearings, the connections must be broken in the reverse order as they were made, the bearings removed and replaced, and the assembly repeated. Thus, to gain access to the bearings requires removal of many unrelated parts. This complicates bearing replacement and makes such replacement very time consuming.
Some improvement has been achieved by adapting the bowl assembly to receive a bearing cartridge in which the upper and lower bowl bearings are fitted. This allows bearing changes to be accomplished by merely replacing the bearing cartridge. The replacement of bearings is thereby simplified, but, in some cases, the flow of flushing fluid to the lower bowl bearing may still be inadequate and premature failure of the lower bowl bearing may still occur. Also, wear ring replacement is not addressed in these bearing cartridges.
The foregoing illustrates limitations known to exist in bearings of the bowls of presently available vertical turbine pump designs. It would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.